1. Field of the Invention
This disclosure relates to the non-invasive application of ultrasonic energy to enhance and/or accelerate the process of wound healing, and more particular, to the healing of wounds including ulcers, such as venous ulcers.
2. Description of the Related Art
Venous ulcers on human legs have proven difficult to treat, for example, because of the lack of vascularization in and around the wound.
The term "wound" for the purposes of "wound healing", as used throughout the present disclosure, includes ulcers such as venous ulcers as well as burns, ulcerated wounds due to, for example, diabetes, surgical incisions or other surgical cuttings including stitched surgical cuttings, skin grafts, hair transplants, revascularization, bed sores, tissue dehiscence, and ligament and tendon repair and reconstruction. In general, as used throughout the present disclosure, the term "wound healing" encompasses addressing damage to, repair of, or restoration of soft tissue.
U.S. Pat. No. 4,530,360 to Duarte (hereafter "Duarte"), describes a basic therapeutic technique and apparatus for applying ultrasonic pulses from an ultrasonic applicator placed on the skin at a location adjacent a bone injury. Duarte gives a range of radio frequency (RF) signals for creating the ultrasound, ultrasonic power density levels, a range of duration of each ultrasonic pulse, and a range of ultrasonic pulse frequencies. The length of daily treatment is also described in Duarte. The Duarte patent is incorporated herein by reference.
U.S. Pat. Nos. 5,003,965 and 5,186,162, both to Talish and Lifshey (hereafter "Talish '965" and "Talish '162", respectively) describe an ultrasonic delivery system in which the RF generator and transducer are both part of a modular applicator unit which is placed at the skin location. The signals controlling the duration of ultrasonic pulses and the pulse repetition frequency are generated apart from the applicator unit. Talish '965 and Talish '162 also describe fixture apparatus for attaching the applicator unit so that the operative surface is adjacent to the skin location. In one application described in Talish '965 and Talish '162, the skin is surrounded by a cast.
U.S. Pat. No. 5,211,160 to Talish and Lifshey (hereafter "Talish '160") also describes a fixture apparatus which is mounted on uncovered body parts; i.e. without a cast or other medical wrapping. Talish '160 also describes various improvements to the applicator unit. Each of Talish '965, Talish '162, and Talish '160 is incorporated herein by reference.
U.S. Pat. application Ser. Nos. 08/391,109, 08/388,971, 08/389,148, and 08/367,471, entitled Gel Containment Structure, Locator Method and Apparatus, Apparatus for Ultrasonic Bone Treatment, and Acoustic System for Bone-Fracture Therapy, respectively, provides ultrasonic apparatus and methods which are applicable to wound healing. U.S. Pat. application Ser. Nos. 08/391,109, 08/388,971, 08/389,148, and 08/367,471 are incorporated herein by reference.
In general, an ultrasound carrier frequency between 20 kHz and 10 MHz coupled with a relatively low-frequency modulating signal, such as 5 Hz to 10 kHz, and a spatial peak temporal average acoustic intensity, such as an intensity less than about 100 milliwatts/cm.sup.2, should aid in and should be effective in wound healing.
Heretofore, such techniques have not been applied to heal wounds by internal application of ultrasound, such as using reflection of ultrasonic waves by reflection from internal tissue such as bone.